Lactational Trends in Vitamin B12 Status on Conventional and Restricted-Roughage Rations

• Published in: Journal of dairy science Vol. 55; no. 4; pp. 474 - 479
• Main Authors: Walker, C.K., Elliot, J.M.
• Format: Journal Article
• Language: English
• Published: Champaign Elsevier Inc 01.04.1972; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: dairy cattle
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(72)85518-8

Sixteen Holstein cows were assigned to one of two dietary treatments, control or restricted-roughage, for the first 34 weeks of lactation. Vitamin B12 in rumen fluid, blood serum, liver, milk and urine was monitored at intervals to determine general trends and to test the hypothesis that roughage restriction would alter the B12 status of animals on this treatment. The per cent of total vitamin B12 activity in rumen fluid represented by the vitamin itself was reduced by roughage restriction. This treatment resulted in higher serum, lower liver and milk and higher urine vitamin B12 activity. Lactational trends are described. Interrelationships among variables suggested the possibility that higher serum B12 of cows on restricted roughage might be due in part to vitamin B12 analogues.